242 



THE CHEMISTRY OF THE SUN. 



[CHAP. 



an effect of temperature, long ago recognised, may be seen from 

 a notice of this lithium line in a discourse by Professor Tyndall, 

 reprinted in the Chemical Neivs, and in a letter of Dr. Frank- 

 land's to Professor Tyndall, dated November 7, 1861. This 



Sun. 



Flame of carbonic 

 oxide. 



Arc. 



Flame of cyanogeu 

 fed with oxygen. 



Bunsen. 



Spark. 



Prominences. 



FIG. 90. The various intensities of the lines of Magnesium as seen under 

 different conditions 



Prominences. 

 Sun (general). 

 Spark. 



Flame of cyanogen 

 fed with oxygtn. 



Flame of carbonic 

 oxide. 



FIG. 91. The various intensities of the lines of Magnesium arranged in order of 

 increasing temperatures. 



letter is so important for my argument that I reprint it entire 

 from the Philosophical Magazine, vol. xxii. p. 472. 



; ' On throwing the spectrum of lithium on the screen yesterday, I 

 was surprised to see a magnificent blue band. At first I thought the 

 lithic chloride must be adulterated with strontium, but on testing it 



